In centrifuging apparatus, constituents/components of a given material (e.g., liquid solutions/mixtures) can be separated based upon the variation of their respective densities and the centrifugal forces to which such constituents/components are subjected. Generally, the material is positioned within a centrifuge bowl or rotor which is rotated at a speed such that the various constituents will effectively assume a radial position within the rotor based upon their respective densities (i.e., constituents having higher densities will be closer to the outer rim of the centrifuge rotor than those having lower densities). The particles of the highest density are collected at the outside edge of the rotor. During rotation of the centrifuge rotor, which is often at relatively high angular velocities in order to generate the magnitude of centrifugal forces needed for separation, the temperature of the rotor and the materials contained therein may undesirably change due to the heating affect of air friction. For instance, certain materials and/or constituents may experience undesired degradation at higher ambient temperature. Moreover, certain temperatures may have an undesirable/adverse effect on certain biological samples during centrifuging, or may actually cause an undesirable reaction amongst certain of the constituents. In addition, certain temperatures may impede the separation of certain constituents from the remainder of the material by centrifuging.
Based upon the foregoing, a number of alternatives have been explored for reading and/or maintaining a temperature of a centrifuge and thus the material within the centrifuge rotor. For instance, it is known to enclose the entire centrifuge within a temperature-controlled housing. More particularly, the air within the housing is maintained at the desired temperature so as to maintain the centrifuged material at such temperature by convection. In these types of configurations, given the heat transfer inefficiencies of convection utilizing air as the heat transfer medium, it is important to maintain a tight seal for the housing in order to maintain temperature control. Consequently, any opening of the housing to remove and/or add materials to the centrifuge will thus affect the housing temperature, and upon any subsequent closing of the housing a certain period of time will be required before the desired steady-state temperature is once again reached.
In contrast to attempting to maintain the temperature of the entire centrifuge by utilizing the above-described types of temperature-controlled housings, other apparatus have attempted to directly cool or heat only the periphery of the centrifuge chamber that contains the centrifuge rotor.
Temperature control systems have also been incorporated on other types of rotating apparatus. For instance, certain analyzers are available in which a plurality of cuvettes are positioned on an outer portion of a rotor. These cuvettes typically have a relatively small volume for receiving at least two different constituents which are initially maintained in separate but interconnected cavities in the rotor. As a result of the centrifugal forces created by rotation of the rotor at a certain speed, the constituents from the separate cavities enter a radially aligned cuvette. The reaction of the two constituents in each cuvette is then monitored and/or analyzed. Since the reaction of the constituents is often temperature-sensitive, heating devices are often employed so as to maintain the peripherally-positioned cuvettes and their constituents at a certain temperature.
Various temperature control alternatives have been explored for cuvette rotors which are generally of the above-described type. For instance, hot air has been used to control either the temperature of an entire housing in which the cuvette rotor is positioned, or at least the space between the periphery of the rotor, which again contains the cuvettes, and the rotor housing. Other apparatus have incorporated heating elements directly on the periphery of the rotor substantially adjacent to the cuvettes to provide for a conductive heat.
However, the above-noted temperature control techniques are only as good as the calibration of the temperature sensor used in reading the data. Thus, there remains a need for a temperature control system which may be readily adapted for use with centrifuges of a variety of configurations, and which effectively records the temperature of substantially the entire centrifuge bowl and materials contained therein without significantly impacting the structure of an existing centrifuge and/or without requiring extensive modifications/additions to the centrifuge and its surroundings and/or requiring extensive field adjustments.
Centrifuges currently employed in laboratories are generally operated by manual controls using various settings and procedures. A rotor control may be used to set the centrifuge to a specific sized or type of rotor. A temperature control and timer are also frequently used depending on the type of sample being tested. There are conventional power switches to manually turn the units on or off as needed. A physical key lock is commonly used to secure centrifuge access from operation. Screwdriver adjusted sensors or trimmers are traditionally used to correct the setting of the temperature sensor. This adjustment is exceedingly time consuming, inaccurate, and prone to drifting. It is also inconvenient to perform the calibration in this manner at customer installation or in the field.
The present invention overcomes the prior art problems by utilizing a digital memory having correction coefficients resulting in the temperature sensors being pre-calibrated.